Class X SCIENCE PWT-1 QUESTION PAPER

CHEMISTRY -13 MARKS

1. The chemical reaction between Hydrogen sulphide and iodine to give Hydrogen iodide and Sulphur is given below:            H₂S + I₂ → 2HI + S                                 

The reducing and oxidizing agents involved in this redox reaction are:                         1

A) Iodine and Sulphur, respectively 

B) Hydrogen Sulphide and Iodine respectively 

C)Sulphur and iodine, respectively 

D)Hydrogen sulphide and Sulphur, respectively                 

2.What type of reaction is an exothermic reaction?              1

a) Decomposition reaction  

b) Displacement reactions  

c) Combustion reaction  

d) Redox reaction 

3. One of the following does not happen during a chemical reaction. This is:   1

(a) Breaking of old chemical bonds and formation of new chemical bonds. 

(b) Formation of new substances with entirely different properties. 

(c) Atoms of one element change into those of another element to form new products. 

(d) A rearrangement of atoms takes place to form new products. 

4. An acid which can decolorize purple colored potassium permanganate solution is:        1

(a) sulphuric acid                                      

(b) citric acid 

(c) carbonic acid                                       

(d) hydrochloric acid 

5. Assertion (A): Fe₂O₃ + 2Al ------> Al₂O₃ + 2Fe 

The above chemical equation is an example of a displacement reaction.                      1

Reason (R): IRON is more reactive than ALUMINIUM, Produces IRON metal from its oxide. 

a) Both A and R are true and R is the correct explanation of A. 

b) Both A and R are true but R is not the correct explanation of A. 

c) A is true but R is false. 

d) A is false but R is true  

6.  A) Why is silver chloride stored in dark bottles?                                                 2

B) What happens when blue colored crystals of copper sulphate are heated? 

7.What is a chemical equation? Describe one activity each to show that a chemical change has occurred in which (i) change of color ,and (ii) change in temperature has taken place                      2

8. A solution of a substance 'X' is used for testing carbon dioxide. Identify 'X'. What will be its reaction with carbon dioxide? Write a balanced equation for the reaction        2

9. When lead nitrate is heated strongly in a boiling tube, two gases are liberated (with brown fumes), and a yellow solid residue is left behind in the test tube:                   (3)

I) Name the type of chemical reaction and define it. 

II) Write the name and formula of the colored gas liberated. 

III) Write the balanced chemical equation for the reaction.  

Biology (13 marks)

Section A: Multiple Choice Questions (MCQs) (1 mark each)

    1.     Which of the following is not a function of chlorophyll in the process of photosynthesis?

     a)     Absorbing sunlight

 b)    Splitting water molecules

c)     Forming glucose

d)    Increasing the temperature of the leaf

     2.     In human beings, where does the process of digestion of starch begin?  

      a)     Stomach

      b)    Mouth

      c)     Small intestine

      d)    Large intestine

    3.     What is the role of the enzyme pepsin in the stomach?

     a)     It digests proteins

     b)    It digests fats

     c)     It digests carbohydrates

     d)    It emulsifies fats

     Section B: Assertion and Reasoning (1 mark each)

For question numbers 5, 6 two statements are given- one is Assertion (A)and the other

is Reason (R). Select the correct answer to these questions from the options A, B, C, D as given

below: -

A Both Assertion and Reason are true and Reason is the correct explanation of Assertion.

B Both Assertion and Reason are true, but Reason is not the correct explanation of Assertion

C Assertion is true, but Reason is false

D Assertion is false, but Reason is true.

4.     Assertion (A): The process of nutrition in plants is called photosynthesis.

Reason (R): Plants take in carbon dioxide from the air and water from the soil to make their food in the form of glucose.

5.     Assertion (A): The human stomach has a highly acidic environment.

Reason (R): The acidic environment helps in killing harmful bacteria and activates pepsin for protein digestion.

Section C: Case Study-based Question (4 marks)

Case Study:

Rhea is a student who is learning about human nutrition. During a class, her teacher explained how the digestive system breaks down food and absorbs nutrients. Rhea learned that the mouth, stomach, and small intestine play key roles in digestion. She also discovered that enzymes like amylase, lipase, and pepsin help break down complex substances into simpler ones.

1.     Based on this case, answer the following questions:

      a)     What is the role of amylase in the digestive process?

      b)    Why is it important for the small intestine to have a large surface area?

      c)     What happens in the stomach during digestion?

      d)    How does the absorption of nutrients take place in the small intestine?

      Section D: Long Answer Questions (2 marks each)

      2.     Explain the process of protein digestion in human beings.

      3.     What is dark reaction?

Physics (13 marks)

Section A – 1 Mark Each (3× 1 = 3 )

Q1. Define the radius of curvature of a spherical mirror.

Q2. What is the nature of the image formed by a concave mirror when the object is placed at infinity?

Q3. Write the relationship between focal length and radius of curvature of a spherical mirror.

 

Section B – 2 Marks Each (3 × 2 = 6 Marks)

Q5. Draw a ray diagram to show image formation by a concave mirror when the object is placed at the focus.

Q6. List two uses of concave mirrors based on their image-forming properties.

Q7. An object is placed 20 cm in front of a concave mirror of focal length 10 cm. Find the position of the image using the mirror formula. (Give proper signs)

 

Section C – Case Study Based Question (1 × 4 = 4 Marks)

Read the following case and answer the questions:

Rita was getting ready for a function. She stood close to her makeup mirror and observed a large, erect image of her face. Curious, she slowly moved away from the mirror and noticed that the image became inverted and smaller. Her brother explained that the mirror behaves differently depending on how close or far the object is.

Q8.1 What type of mirror is used in the makeup mirror?

Q8.2 What is the nature of the image formed when Rita is very close to the mirror?

Q8.3 What happens to the image when Rita moves beyond the center of curvature?

Q8.4 Why is this type of mirror suitable for use as a makeup mirror?

Carbon and its compounds- important MCQ , assertion-reason and case study based questions

MULTIPLE CHOICE QUESTIONS

1.  Pentane has the molecular formula C5H12. It has

(a)   5 covalent bonds

(b)   12 covalent bonds

(c)   16 covalent bonds

(d)   17 covalent bonds

2.  Identify the unsaturated compounds from the following

(i) Propane (ii) Propene (iii) Propyne (iv) Chloropropane

(a)   (i) and (ii)

(b)   (ii) and (iv)

(c)   (iii) and (iv)

(d)   (ii) and (iii)

3.  In which of the following compounds, — OH is the functional group?

(a)   Butanone

(b)   Butanol

(c)   Butanoic acid

(d)   Butanal

4.  The hetero atoms present in CH3-CH2-O-CH2-CH2-Cl are

(i) oxygen (ii) carbon (iii) hydrogen (iv) chlorine

(a)   (i) and (ii)

(b)   (ii) and (iii)

(c)   (iii) and (iv)

(d)   (i) and (iv)

5.  Oils on treating with hydrogen in the presence of palladium or nickel catalyst forms fats. This is an example of

(a)   addition reaction

(b)   substitution reaction

(c)   displacement reaction

(d)   oxidation reaction

6.  The carbon exist in the atmosphere in the form of

(a)   Carbon monoxide only

(b)   Carbon monoxide in traces and carbon dioxide

(c)   carbon dioxide only

(d)   coal

7.  Buckminsterfullerene is an allotropic form of

(a)   phosphorus

(b)   sulphur

(c)   carbon

(d)   tin

8.  The functional group present in propanal is-

(a)   -OH

(b)   -COOH

(c)   -CO-

(d)   -CHO

9.  When vegetable oil is treated with hydrogen in the presence of nickel Or (Palladium) as a catalyst, it forms vegetable ghee. This process shows

(a)   Anodising reaction

(b)   Substitution reaction

(c)   Displacement reaction

(d)   Addition reaction

10.   The number of structural isomers for alkane with a molecular weight 72 is

(a) 2

(b) 3

(c) 4

(d) 5

11.   Which of the following is incorrectly matched?

(a)   Vinegar → carboxylic acid

(b)   C2H6 → alkane

(c)   Ethanol → alcohol

(d)   Methanol → ketone

13  While cooking, if bottom of the vessel is getting blackened on the outside, it means that

(a)   The food is not cooked properly

(b)   The fuel is not burning properly

(c)   The fuel is wet

(d)   The fuel is burning completely

14. The chemical reaction shows the addition of chlorine gas to hydrocarbon in the presence of sunlight.

CHCl3 + Cl2 → CCl4 + HCl

How does chlorine react to a hydrocarbon compound in the presence of sunlight?

(a)   it adds hydrogen into the compound

(b)   it adds an oxygen atom into the compound

(c)   it substitutes hydrogen atom from the compound

(d)   it breaks double and triple bonds into a single bond

15.  A carbon compound contains two atoms of carbon. Which name should the carbon compound bear?

(a)   Butane

(b)   Ethane

(c)   Methane

(d)   Propane

16.     The electronic configuration of an element is found to be 2, 4. How many bonds can one carbon atom form in a compound?

(a) 1

(b) 2

(c) 4

(d) 6

CASE STUDY BASED QUESTIONS

1.  The compounds which have the same molecular formula but differ from each other in physical or chemical properties are called isomers and the

phenomenon is called isomerism. When the isomerism is due to difference in the arrangement of atoms within the molecule, without any reference to

space, the phenomenon is called structural isomerism. In other words.

Structural isomers are compounds that have the same molecular formula but different structural formulas, i.e., they are different in the order in which different atoms are linked. In these compounds, carbon atoms can be linked together in the form of straight chains, branched chains or even rings.

i.  Which of the following sets of compounds have the same molecular formula?

(a)   Butane and iso-butane

(b)   Cyclohexane and hexene

(c)   Propanal and propanone

(d)   All of these

ii.  In order to form branching, an organic compound must have a minimum of carbon atoms

(a) 2

(b) 3

(c) 4

(d) 5

iii.  Which of the following is an isomeric pair?

(a)   Ethane and propane

(b)   Ethane and ethene

(c)   Propane and butane

(d)   Butane and 2-methylpropane

iv.  Among the following the one having longest chain is

(a)   neo-pentane

(b)   iso-pentane

(c)   2-methylpentane

(d)   2,2-dimethylbutane

v.  The number of isomers of pentane is

(a) 2

(b) 3

(c) 4

(d) 5

2.  Nisha observed that the bottoms of cooking utensils were turning black in colour while the flame of her stove was yellow in colour. Her daughter

suggested cleaning the air holes of the stove to get a clean, blue flame. She also told her mother that this would prevent the fuel from getting wasted.

i.     Identify the reasons behind the sooty flame arising from the stove.

ii.     Can you distinguish between saturated and unsaturated compounds by burning them? Justify your answer.

iii.     Why do you think the colour of the flame turns blue once the air holes of the stove are cleaned?

2.  Food, clothes, medicines, books, or many of the things are all based on this versatile element carbon. In addition, all living structures are carbon based. The earth’s crust has only 0.02% carbon in the form of minerals. The element carbon occurs in different forms in nature with widely varying physical properties. Both diamond and graphite are formed by carbon atoms, the

difference lies in the manner in which the carbon atoms are bonded to one another. Carbon has the unique ability to form bonds with other atoms of carbon, giving rise to large molecules. This property is called catenation.

i.  From the given alternatives, whose chemical and physical properties are not same?

(a)   Graphite and Diamond

(b)   Phosphorous and Sulphur

(c)   Carbon and Hydrogen

(d)   Methyl alcohol and Acetic acid

ii.  Which of the following statements is not correct?

(a)   Graphite is much less dense than diamond

(b)   Graphite is black and soft

(c)   Graphite has low melting point

(d)   Graphite feels smooth and slippery

iii.  Which of the following are isomers?

(a)   Butane and isobutene

(b)   Ethane and ethene

(c)   Propane and propyne

(d)   Butane and isobutane

iv.  Which one of the following is not an allotrope of carbon?

(a)   Soot

(b)   Graphite

(a)  Diamond

(b)   Carborundum

v.  Pentane has the molecular formula C5H12. It has

(a)   5 covalent bonds

(b)   12 covalent bonds

(c)   16 covalent bonds

(d)   17 covalent bonds

ASSERTION AND REASON QUESTIONS

DIRECTION: Each of these questions contains an Assertion followed by Reason. Read them carefully and answer the question on the basis of following options. You have to select the one that best describes the two statements.

(a)   Both A and R are true and R is the correct explanation of A.

(b)   Both A and R are true but R is not the correct explanation of A.

(c)   A is true but R is false.

(d)   A is false but R is true.

1.  Assertion (A): Carbon is the only element that can form large number of compounds.

Reason (R): Carbon is tetravalent and shows the property of catenation.

Ans. A is false but R is true.

2.  Assertion (A): Diamond and graphite are allotropes of carbon.

Reason (R): Some elements can have several different structural forms while in the same physical state. These differing forms are called allotropes.

Ans. Both A and R are true and R is the correct explanation of A.

3.  Assertion (A): In alkanes, alkenes and alkynes the valency of carbon is always four.

Reason (R): All hydrocarbons except alkanes contain double bonds.

Ans. (c) A is true but R is false.

1.  Assertion (A): The functional group present in alcohols is – OH.

Reason (R): It is the same group as present in water, hence water and alcohol have similar properties.

Ans. (c) A is true but R is false.

2.  Assertion (A): Carbon monoxide is extremely poisonous in nature.

Reason (R): Carbon monoxide is formed by complete combustion of carbon.

Ans. (c) A is true but R is false.